What are your connection speeds?
Where are you two located in terms of: Are you both in the same State? County, Country?
The Kill Cam Doesn't Lie? The Game Does! Who gets the advantage, and how is this determined? I can post videos ALL day with me shooting someone in HC even, with 10-15 arounds at the minimum dead on and either not get hitmarkers altogether, or not get the kill, but turned on.
Keeping in mind that my interenet isn't fiberoptic, but the best money can by prior to that.